The article reviews the discovery and biological properties of Neutrophil-activating Peptide-1/Interleukin 8 (NAP-1/IL-8), a novel cytokine that activates neutrophils. Neutrophils are key components in inflammation and tissue damage, particularly in bacterial infections. NAP-1/IL-8, initially identified as a monocyte-derived neutrophil chemotactic factor, has been shown to induce a wide range of functional responses in neutrophils, including motility, adhesion, enzyme secretion, and reactive oxygen species production. The peptide shares structural similarities with other neutrophil-activating peptides like C5a and formylmethionyl peptides but exhibits unique characteristics, such as selectivity for neutrophils and resistance to degradation. NAP-1/IL-8 is produced by various cell types, including monocytes, endothelial cells, and fibroblasts, in response to inflammatory stimuli like IL-1 and TNF. Its role in diseases such as psoriasis, arthritis, and respiratory disorders suggests its potential as a therapeutic target. The article also discusses the mechanism of action, signal transduction pathways, and the expression of NAP-1/IL-8 in different tissues, highlighting its importance in understanding and treating inflammatory conditions.The article reviews the discovery and biological properties of Neutrophil-activating Peptide-1/Interleukin 8 (NAP-1/IL-8), a novel cytokine that activates neutrophils. Neutrophils are key components in inflammation and tissue damage, particularly in bacterial infections. NAP-1/IL-8, initially identified as a monocyte-derived neutrophil chemotactic factor, has been shown to induce a wide range of functional responses in neutrophils, including motility, adhesion, enzyme secretion, and reactive oxygen species production. The peptide shares structural similarities with other neutrophil-activating peptides like C5a and formylmethionyl peptides but exhibits unique characteristics, such as selectivity for neutrophils and resistance to degradation. NAP-1/IL-8 is produced by various cell types, including monocytes, endothelial cells, and fibroblasts, in response to inflammatory stimuli like IL-1 and TNF. Its role in diseases such as psoriasis, arthritis, and respiratory disorders suggests its potential as a therapeutic target. The article also discusses the mechanism of action, signal transduction pathways, and the expression of NAP-1/IL-8 in different tissues, highlighting its importance in understanding and treating inflammatory conditions.